Hydraulic pumps or motors of the rotating barrel-type

ABSTRACT

A hydraulic pump or motor has a fixed cylindrical casing provided with a bottom having a slide face with first and second orifices formed therein. A barrel is supported in the casing for rotation about an axis and has cylinders with pistons sliding therein. The cylinders are alternately put into communication with the first and second orifices. The barrel is connected to a shaft for rotation therewith. A bearing is provided inside the barrel between the barrel and a support therefor. The bearing is of a small diameter and disposed at the point of application on the axis of said barrel of the resultant of shearing forces applied to said pistons so as to absorb these forces. The bearing is so constructed as to permit the barrel to effect slight angular movements with respect to said support and therefore with respect to the axis of rotation of said shaft. A plate is provided for reciprocably moving the pistons. The plate comprises two laterally spaced convex cylindrical portions having a common axis and a common diameter and arranged symmetrically with respect to the geometric axis of said shaft by which it is supported against two elements having a recess with a shape complementary to that having a recess with a shape complementary to that of said convex portion. These elements are rigidly fixed to said support and form an integral part thereof such that said plate can thereby pivot with respect to said support.

United States Patent [111 ,6 1,7

[72] Inventor Rene Lucien 3,396,670 8/1968 Baits 103/ 162 Hauts De Seine, France 3,426,686 2/ 1969 Anderson 103/ 162 E m Primary Examiner-William L. F reeh Patented 1972 Attorney-Waters, Roditi, Schwartz & Nissen [73] Assignee Messier Paris, France ABSTRACT: A hydraulic pump or motor has a fixed cylindri- Pnomy 41 1967 cal casing provided with a bottom having a slide face with first France and second orifices formed therein. A barrel is supported in [31] 130,810 the casing for rotation about an axis and has cylinders with pistons sliding therein. The cylinders are alternately put into [54] HYDRAULIC PUMPS 0R MOTORS OF THE communication with the first and second orifices. The barrel is ROTATING BARREL TYPE connected to a shaft for rotation therewith. A bearing 18 pro- 1 Claim 5 Drawing Figs vrded inside the barrel between the barrel and a support therefor. The bearing is of a small diameter and disposed at [52] US. Cl 91/506, the point of application on the axis of aid barrel of the 417/ 222 resultant of shearing forces applied to said pistons so as to ab- [51] Int. so -b the e fo -ces The bearing is so constructed as to permit F04!) 1/26 the barrel to effect slight angular movements with respect to Fleld of Search aid upport and therefore with respect t0 the axis of rotation 230/178; 91/198, 485, 504-506; 1 218 of said shaft. A plate is provided for reciprocably moving the pistons. The plate com rises two laterally spaced convex [56] References cued cylindrical portions having a common axis and a common UNITED STATES PATENTS diameter and arranged symmetrically with respect to the 2,409,185 10/1946 Blasutta 103/ 162 geometric axis of said shaft by which it is supported against 2,945,449 7/1960 Le Febvre et a1. 103/ 162 X two elements having a recess with a shape complementary to 2,525,498 10/1950 Naylor et a1. 103/162 that having a recess with a shape complementary to that of 2,588,866 3/1952 Moon 103/ 162 said convex portion. These elements are rigidly fixed to said 2,925,046 2/ 1960 Budzich 103/ 162 support and form an integral part thereof such that said plate 3,092,034 6/1963 Bartholomaus 103/162 can thereby pivot with respect to said support.

III In HYDRAULIC PUMPS OR MOTORS OF THE ROTATING BARREL-TYPE The present invention relates to improvements in hydraulic pumps or motors of the rotating barrel type. It is more particularly concerned with improvements made to the articulation system of the actuating plate of the pistons of the pumps or motors of this kind on the fixed frame of these devices.

These improvements have been more particularly developed for the purpose of their applications to the hydraulic pump or motor which forms the subject of the U.S. Pat. application Ser. No. 598,410, now U.S. Pat. No. 3,545,388 filed on Dec. 1, 1966 in the name of the present applicant, and the invention in consequence also relates to a pump or a motor of this type when provided with the said improvements.

It will be recalled that in a pump of this type, the barrel is mounted floating. A bearing of small diameter is arranged in the interior of the barrel with the object of taking up the shearing forces due to the pressure substantially level with the point of application of their resultant, at the same time ensuring for the barrel the degree of freedom of movement which is necessary so that it can be constantly applied in a perfect manner against the plate or face in which are formed the suction and delivery orifices of the pump. The bearing which takes up the shearing forces is interposed between the barrel and a supporting member which is anchored to the bottom of the pump and through which passes the driving shaft of the barrel.

In the pump described in the main application, theactuating plate of the pistons pivots on two bearings carried by the pump body. Tests which have subsequently been carried out by the applicants have shown however that this conventional solution is ill suited to conditions of use which result in large forces. Due to the bearings with which it is provided, the pump body is in fact subjected to high bending moments. In addition, the plate and the body of the pump have a tendency to be deformed, due to the large forces to which they are subjected.

The present invention has for its object to remedy these drawbacks by articulating the actuating plate on the fixed frame of the pump, without utilizing bearings fixed on the pump body.

In accordance with the invention, the plate is provided on its rear face with two cylindrical convex portions, having the same axis and the same diameter, disposed symmetrically with respect to the central plane of the plate, the said convex portions being supported against two concave portions of complementary form, arranged in the support of the bearing which takes up the shearing forces, for example, by means of needle bearings which roll without sliding on the rolling tracks constituted by the said concave portions, the said plate being thus able to pivot with respect to the said support about the geometric axis common to the cylindrical surfaces of the said convex and concave portions.

This form of construction of the pump described in the above-mentioned patent has the advantage that the plate may have a form such that the point of application of the resultant of the pressure forces to which it is subjected is very close to one of the supporting surfaces of the plate against the support, so as to reduce the deformation of the said plate to a minimum. In addition, as this resultant is taken up by the support, no bearing is fixed on the pump body which is thus not subjected to large bending moments and is not appreciably deformed, so that it can be given a considerably simpler form.

One form of embodiment of the invention will be described in detail below, by way of example and not in any limitative sense, reference being made to the accompanying drawings, in which:

FIG. 1 is an axial cross section of the pump;

FIG. 2 is a half section taken along the line ll-Il of FIG. 1;

FIG. 3 is a cross section taken along the line IIlIll of FIG. 1, the moving parts and the plate being assumed to have been removed;

FIG. 4 is a rear view of the actuating plate;

FIG. 5 is a partial cross section, in side elevatiomof the part of the support of the bearing which takes up the shearing forces, which cooperates with the actuatingplate.

The pump shown in the drawings is a pump which is selfregulating by variation of the cylinder capacity per revolution as a function of the delivery pressure, of the type described in the above-mentioned application.

This pump will therefore not be described in detail, but'it will be recalled that it comprises a barrel 1 driven in rotation by a shaft 2 through the intermediary of a sleeve 3 having internal and external splines. This barrel is supported on a domed portion of a hollow support 4'by means of needles 5 which constitute, in the interior of the barrel, a bearing for taking up the shearing forces level with the point of application of the resultant of these forces. The support 4 is rigidly anchored to a flange 6. In the cylinders 7a of the barrel slide pistons 7b, which are coupled to a plate 8 by shoes 9, these being in turn maintained by a plate 10a which slides over the retaining ring l0b. These shoes are supported against the plate 8 through the intermediary of the plate 10.

The distribution is effected by a fixed face 12a applied against the bottom 12 or forming an integral part of this latter. This face is provided with two openings, in communication with suction and delivery orifices. At each rotation of the barrel, these openings are put successively into communication with orifices formed in the bottom of each of the cylinders 7a. When starting up or in the absence of delivery pressure, the barrel 1 is applied against the face 12a by a spring 13-which is supported against the shaft 2 through the intermediary of a ring 14, and at its other extremity on the radial web of the sleeve 3. The force of this spring is taken-up by a bearing 15.

In accordance with the invention, the plate 8 is provided laterally on its rear face with two convex cylindrical portions 8a and 8b having the same axis and the same-diameter, being symmetrically arranged with respect to the central plane of the plate (see FIG. 4.).

Through the intennediary of two shoes of needles l9a-and 19b (see FIGS. 3 and 5), these portions are applied against two concave cylindrical surface portions20a and 20b, concentric with the preceding and machined in the support 4 or fixed on this support.

The plate 8 thus pivots on the support 4 about the axis common to the cylindrical surfaces described above.

During operation, the plate 8 is applied against the support 4 by the pressure forces. When the delivery pressure is zero, a piston 22 sliding in a cylinder 22a of the pump body, is pushed back by a spring 21, or by any other means known per se, in the direction of a ring 24, fixed on the plate 8 by screws 25, and on which the piston 22 acts through the intermediary of a roller 23.

Plates 26 fixed on the support 4 by screws 27 playthe part of an abutment for the shoes of needles 19a and 19b, grids 19c guiding the needles 19d of the shoes. These grids have a developed length smaller than that of the concave'portions 20a and 20b, the difference being such as to permit the needles 19d to roll without sliding on the portions 8a and 8b on the one hand and 20a and 20b on the other, as soon as the grids have come into abutment against one of the plates 26.

As is well known with this type of pump, the maximum inclination of the plate 8 is ensured, whenstarting up, by the action of a spring, and as soon as the delivery pressure is established, by the action of the pressure forces. When this delivery pressure reaches a value known as the regulation pressure, it displaces a slide valve (not shown) which then controls a piston 28 so as to regulate the inclination of the plate 8 through the intennediary of a roller 29.

In addition to the advantages already referred to, it will be noted that it is possible to give a large surface to the needle shoes 19a, 19b and to the concave cylindrical portions 20a, 20b on which the plate 9 pivots, in order to reduce the surface pressures to which these parts are subjected.

The form of embodiment which has just been described has not of course any limitative nature and modifications in the field of those skilled in the art may be made thereto without thereby departing from its scope.

Thus, for example, the needle shoes may be dispensed with, the surfaces in contact of the plate and the support being in this case formed of a light-friction material in such manner as to form journal bearings. Similarly, the piston 22 may be subjected, when so required, to the delivery pressure of the pump so as to apply on the plate 8 a compensating force which tends to give it an inclination.

What I claim is:

1. ln a hydraulic pump or motor comprising a fixed cylindrical casing provided with a bottom having a slide face with first and second orifices formed therein; a barrel supported in said casing for rotation about an axis, said barrel having cylinders and pistons sliding in said cylinders; means for putting said cylinders alternately into communication with said first and second orifices in said slide face; means for reciprocally moving said pistons in said cylinders and producing forces on said pistons having components acting as shearing forces applied to said barrel; a rotatable shaft; means for connecting said barrel to said shaft for rotation therewith; a support to said casing; and a bearing inside the barrel between said support and said barrel, said bearing being of small diameter and disposed at the point of application on the axis of said barrel of the resultant of the shearing forces applied to said pistons so as to absorb said shearing forces, said bearing being so constructed as to permit said barrel to effect slight angular movements with respect to said support and therefore with respect to the axis of rotation of said shaft, the improvement wherein said means for reciprocally moving said pistons comprises a plate to which said pistons are coupled and means permitting the inclination of said plate with respect to the geometric axis of said shaft to be regulated, said plate comprising two laterally spaced convex cylindrical portions having a common axis and the same diameter, arranged symmetrically with respect to the geometric axis of said shaft, by which it is supported against two elements having a recess with a shape complementary to that of said convex portions, said elements being rigidly fixed to said support and forming an integral part thereof, in such manner that said plate can thereby pivot with respect to said support, needle bearings interposed between said convex portions and the corresponding surfaces of said elements, a piston slidably mounted in a cylinder provided in the pump body for acting on said plate to apply the same against said elements, said piston in the pump body extending parallel to the portions in the barrel, an elastic member acting on said pistons urge the piston towards said plate, a ring fixed on said plate, and a roller interposed between said ring and piston for transfer of force from the piston to said plate. 

1. In a hydraulic pump or motor, comprising a fixed cylindrical casing provided with a bottom having a slide face with first and second orifices formed therein; a barrel supported in said casing for rotation about an axis, said barrel having cylinders and pistons sliding in said cylinders; means for putting said cylinders alternately into communication with said first and second orifices in said slide face; means for reciprocally moving said pistons in said cylinders and producing forces on said pistons having components acting as shearing forces applied to said barrel; a rotatable shaft; means for connecting said barrel to said shaft for rotation therewith; a support to said casing; and a bearing inside the barrel between said support and said barrel, said bearing being of small diameter and disposed at the point of application on the axis of said barrel of the resultant of the shearing forces applied to said pistons so as to absorb said shearing forces, said bearing being so constructed as to permit said barrel to effect slight angular movements with respect to said support and therefore with respect to the axis of rotation of said shaft, the improvement wherein said means for reciprocally moving said pistons comprises a plate to which said pistons are coupled and means permitting the inclination of said plate with respect to the geometric axis of said shaft to be regulated, said plate comprising two laterally spaced convex cylindrical portions having a common axis and the same diameter, arranged symmetrically with respect to the geometric axis of said shaft, by which it is supported against two elements having a recess with a shape complementary to that of said convex portions, said elements being rigidly fixed to said support and forming an integral part thereof, in such manner that said plate can thereby pivot with respect to said support, needle bearings interposed between said convex portions and the corresponding surfaces of said elements, a piston slidably mounted in a cylinder provided in the pump body for acting on said plate to apply the same against said elements, said piston in the pump body extending parallel to the portions in the barrel, an elastic member acting on said piston urge the piston towards said plate, a ring fixed on said plate, and a roller interposed between said ring and piston for transfer of force from the piston to said plate. 